People have known the Earth is not flat since ancient times.
There is no way to find out your age but habbo age can be found out with badges that you collect. If people know your real age they probably have been told by someone.
Yes
It helps to fill in pieces of the knowledge puzzle.
By huting
5
to go and find wifes and marry people
secured their food
It isn't.
When people mixed Tin and Copper together.
People feel the vibration in the earth suraface
It depends if you want to say how old he is in Narnia or on earth. To find his age on earth you would have to find Peters age in the Lion The Witch And The Wardrobe (Since they are about the same age) and add 5. To find his age in Narnia you would have to find his age in Prince Caspian and add 1.